Electric switch and terminal therefor



' Dec. 1, 1931. H. P. PINKHAM 1,834,178

ELECTRIC SWITCH AND TERMINAL THEREFOR Filed March 26, 1930 lllllll Fiver: 70?.

a unitary brush structure.

terminal portion 30 which is formed by upsetting the end of the stud. Said terminal portion 80, as here shown, is of substantially rectangular section and provides an upper horizontal shoulder 32 and a lower fiat contact attaching face 34 of substantial area. In some instances said terminal portion 30 may constitute, in itself, the main stationary contact member of the switch. The switch herein shown is of the inverted brush type and the main stationary contact member thereof includes a brush member comprising a plurality of superposed laminations having horizontal shank portions 36 and angularly related, downwardly directed toeportions 88 which terminate in a relatively horizontal contact face 40. As shown most clearly in Fig. 4, the shank portions 36 of said laminations are surrounded by a metallic sheath 42 which is substantially coextensive with said shank portions and which serves to connect mechanically the several laminations of the brush whereby to provide The sheath 42 and the shank portions of said laminations are usually mechanically and electrically connected together by solder. Said sheath 42 is provided with an upper plane surface 44 which is adapted to be clamped firmly against the lower face 34 of the terminal portion 80 whereby to provide a relatively extensive area of contact between the contact member and the stud. To this end, vertical passages are provided through the shank portion of said contact member and clamping bolts 48 are extended therethrough and are screw threaded into the threaded passages 46 in the terminal portion 30 of the stud. As shown most clearly in Fig. 3, the clamping bolts 48, of which two are here shown, are disposed in staggered relation on opposite sides of the longitudinal center line through the brush thus to distribute the pressure equally over the contacting surfaces 34 and 44 of said stud and contact member.

Said stud is also provided with an auxilwhich are passed through said arms 52 and are screw threaded into the ends of said contact member. The middle connecting portion 58 of said bracket is secured beneath the heads of the attaching bolts 48 for the main wbrush member and consequently in electrical contact with the brush.

The bridging member 24 of the movable switch member comprises an inverted channel member having the depending side walls 60 and the fiat upper back portion 62, the ends of which constitute horizontal contact faces which cooperate with the contact faces 40 of the main stationary contact members. The movable arcing contact members comprising rollers 64 are supported on bolts 65 between parallel spaced arms 66 which are pivotally supported between the depending sides 60 of the movable brush member and are spring-urged in the usual manner into engagement with the cooperating fixed arcing members 50. y

In accordance with the present invention, means are provided for adjusting the axial conducting stud 16 longitudinally in its supporting bushing 14 whereby to adjust the stationary contact member vertically.

The adjusting means includes a bushing 68 which is located loosely on the stud 16 above the head 30. Said bushing is provided with an externally screw-threaded lower end 7 O, and a hexagonal outstanding flange 72 at its upper end. An annular rib or lip 74 extends above the flange 72 and is located within the insulating spacing tube 76 of the bushing. The upper end of said tube is seated on a washer 78 which is located in an annular groove or recess 80 formed in the lower end of the bushing 14. The lower end of the tube is seated on a washer 84, which, in turn is seated on the upper face of the flange 72. Thus, the clamping pressure is transmitted through said bushing and tube to the insulator 14. The rib 74 holds the tube against axial displacement, An axially-long nut 86 is screw-threaded on the lower end of the bushing 68 and bears against the upper face of' the head 30 of the stud. Thus, by holding the bushing 68 stationary and rotating the nut 86, in'one direction or another, the stud can be raised and lowered in its insulating bushing 14 to adjust the height of the contact members carried by the stud. When the'proper position for the contact members is determined, they are locked in position by means including a nut 88 which is screwthreaded on the screw-threaded upper end 90 of the stud and bears against the upper end of the insulator 14.

In the modification illustrated in Fig. 5, the outstanding flange 68 of the bushing 7 2 is at the bottom of the bushing and bears directly against the upper face of the integral head 30 of the stud. The upper portion of the bushing is located within the insulating tube 76 to holdit against lateral displacement and a nut 86 is threaded on the upper end of the bushing and bears against the lower end of the insulating tube.

The stud 16 is of uniformdiameter above the enlarged head 30 or, at least, is not larger atthe top than at the bottom, so that the bushing 68 can be placed in position thereon.

The above described arrangement has proven to be cheaper than the usual construction and to facilitate the labor of adjusting the position of the stationary contact members. The switch is improved electrically since the head 30 is integral with the stud and thus the usual jointlat this place, withits electrical resistance and'consequent heating and reduction of current-carrying capacity of the switch is eliminated.

l claim:

1. A terminal' for electric-switches com prising the combination of an nsulating bushing, a conducting stud therein which has an upset integral enlarged head at the lower end, a contact member carried by said head,

a screw-threaded sleeve loose on said stud be-; tween said head andthe lowerrend of said bushing, and a member threaded adjustably V stud therein which has a shoulder, a contact member carried by said stud, and an element of Variable length disposed between said abutment and'shoulder and having connected components which are adjustable lengthwise of the stud and which bear respectively upon said abutment and shoulder and constitute means to determine the position of said contact member with respect to said bushing.

3. A terminal for an electric switch comprising the combination of an insulating bushing having an abutment, a conducting stud therein which has a shoulder, a contact member carried by said stud, and a variablelength member disposed between said abutment and shoulder and having two elements which are adjustably screw threaded together and which bear respectively upon said abutment and shoulder and constitute means to determine the position of said contact memher with respect to said bushing.

l. A terminal for electric'switches comprising the combination of an insulating bushing, a conducting stud which extends entirely through said bushing and has a shoulder at its lower end, a contact member carried by the lower end of said stud, means for setting the position of said contact member with respect to said bushing including a variable length member having two elements which are adjustably connected together by said threads and which bear respectively upon said shoulder and upon the lower end of said bushing, and a clamping'member which is screw threaded upon the upper end of said stud and bears against the upper end of said bushing.

5. A terminal for electric switches comprising the combination of an insulating bushing a conducting stud therein having a shoulder which confronts the lower end of the bushing, a contact member carried by the stud, and means for settingtthe positzi on ofi:

said contactmember with respect to the bushing including ,a screw threaded bushing: A

which surroundssaid stud between said shoulder and insulating. bushing and has a nut,

screw threaded thereon, said screw threaded bushing and said (nut bearingyseparately' on said shoulderand the end of said insulating bushing;

6. A terminal 1 for electric switches com prising athe combination of an insulating bushing, a1 conducting stud therein having a shoulder which confronts the lower end of the,

bushing, a contact member carried by the stud, means for setting the position of said contact member with: respectto the bushing including a screw threaded bushing which surrounds said stud between said shoulder and insulating bushing and has a nutzscrew threaded' thereon, said screw threaded bush-- ing and said nut bearing separatelyxonsaid shoulder and the endof said insulating bush ing, anda member having a screw-threadedv connection with the upper end ofv said stud and bearing on the upper end of said insulating bushing.

7. [A terminal for electric switches compris- 7 ingthe combination of an insulating bushing, a conducting stud therein having a shoulder;

a contact member carried by said stud below said shoulder,- means which determines the position of said contact member with respect to said bushing includinga memberwhich is interposed between said shoulder and the end' of's'aid bushing and bears against both and has means by which it is variable as to its axial length, wherebyzto define the spacing between said 1 shoulder and fbushing, and

means carried by-the upper end of said stud which applies axial end Qfsaid bushing.

8. A terminal for-electric switches com-v Erising the combination of an insulating ushi'ng, a conducting stud therein having an" enlarged head at its lower end, a contact member carried by said: head, a sleeve loose on'saidstud between said head and the lower end of saidbushing and havingan outstandingshoulder which bears uponthe'lower end of saidbushing, and a nut screw threaded on bears against said head. 5- V I V 9. A terminal for electric switches comsaid sleeve andmovable axially thereon which prising the combination of an insulating bushing, a conducting stud therein-having an enlarged head located below the lower end I of the bushing, acontact member carriedby said he ad, an insulating tube which surrounds said-studabove vsaid head and hasits upper" endbearing upon the lower end of said bushing, and means which defines the position of said cont act member with respect to said "bush- 'ing including a variable-length member-interposed between said head and the lower'endof said. tube and having means which engages.

pressure on the upper the lower en-d of said tube.

10. A terminal for electric switches com prising the combination of an insulating bushing, a conducting stud therein having: an enlarged head at the lower end thereof, a con- 1 tact member carried by said head, an insulating tube surrounding said stud above said head and under saidbushing, and having its upper end seatedonthe lower end of said bushing, and means to define the position of said contact member with respect to said bushing-including a sleeve which is loose on said stud and which extends into said tube and constitutes means to hold it against lateral displacement, said sleeve having anoutstanding flange which is seated upon the bottom ofsai-d tube and having a screw threaded portion beneath said flange, and a nut screw threaded on said sleeve and bearing upon said head.

11. A stationary switch member for an electric switch including a tubular insulating bushing, an axialc-onducting stud extended through said bushing having an integral en larged end portion, an exteriorly screw threadedsleeve disposed on said conductor adjacent saidenlarged end portion, an abutment member screw threaded on said sleeve, said sleeve and abutment member bearing separately on said enlarged end portion and on the end ofsaid bushing, and a clamping nut screw threaded on the upper end of said stud and arranged to bear against the upper end. of. said insulating bushing.

12. An electric switch-terminal comprising the combination of a tubular insulating bushing having an axial passage therethrough, a rigid conducting stud received within and extended through said passage at both ends thereof and having its lower end upset whereby to provide an enlarged contact attaching portion which "is integral therewith, a c-ontact'member for the switch carried by the upset end portion of said stud and attaching bolts passed through said contact member and screw threaded into said stud for clamping said contact member detachably to said stud.

13. An leliactricswitch terminal comprising the'combination of a tubular insulating bushingliaving an axial passage therethrough, a rigid conducting stud received within and extended through said passage at both ends thereof and having its lower end ,upsetwhereby toprovide an enlarged contact attaching portion which is integral therewith, a contact member for the switch carried by the upset end portion of said stud, at-

tachin bolts oassed throu h said contactc: r: member and screw threaded into said stud for clamping said contact member detachably to said stud, and means securing said stud fixedly in said bushing in a plurality of axially adjusted positions.

14. An electric switch terminal comprising the combination of a tubular insulating bushing having an axial passage therethrough, a rigid conductor received within and extended through said passage at both ends thereof and having its lower end upset whereby to provide an end portion of increased cross sec tional area, a contact member having a flat upper face located in contact with the enlarged lower end of said stud, clamping bolts passed through said contact member and screw threaded into said stud, an abutment member for the lower end of'said bushing surrounding said stud adjacent the upset end portion thereof and capable of axial adjust ment thereon, and clamping means at the upper ext-ended end of said stud arranged to engage the upper end of said bushing whereby to urge said abutment member into engagement with the lower end of said bushing.

In testimony whereof, I have signed my name to this specification.

HENRY P. PINKHAM.

ion 

